The Minister for Higher Education has ruled out ringfencing college places for students who sat the Leaving Cert in previous years.
Thousands of pupils who sat the State exams in recent years have raised significant concerns that they will miss out on third level places because of grade inflation.
The calculated grades process has resulted in marks that are, on average, 4.4% higher than those of last year.
Simon Harris has said it is "likely" that points for third level courses will jump as a result with CAO points due out on Friday, but he said he would not be providing specific places for those from previous years.
He said: "The legal advice available to me is that if I ringfence places that you actually end up creating further legal complications."
He said the "fairest" and "most equitable way" to address the issue is to provide more college places.
However, Sinn Féin TD Rose Conway-Walsh accused the Government of "playing brinkmanship" with Leaving Cert students of previous years by failing to address the issue of increased points required for 2020 to access third-level.
“The Minister is attempting to brush aside the real problem by claiming that the Government has made over 5,000 new third-level places available," she said.
Ms Conway-Walsh said it is disingenuous to claim the increase in places will solve the problem and said it does not tell the real story. She said over 4,000 new places are needed this year to meet the increase in demand even before the challenges presented by Covid-19.
She said: "So, while there may have been some increase in places, it is not going to be anywhere near enough to address the disadvantage students from previous years face in reapplying."
Acknowledging that many students will be anxious, Mr Harris said he is hoping to provide even more places ahead of this Friday when first-round CAO offers are made.
He said: "I do expect the points demands to be higher this year. That's why we have taken the actions that we've taken.
"I would say to students today to have your plan A, and I hope you get it, but also have your plan B. There are always other ways of getting to where you want to get," the Minister told RTÉ's
.Mr Harris is expected to announce 500 more additional third-level places today after making 1,200 extra earlier in the week.